1. Field of Invention
The present invention relates to the delivery of pressurized liquids, and, more particularly, to a method and device for reducing the pressure of a liquid flowing through a pressurized liquid system to a desired level.
2. Discussion of Related Art
In a liquid delivery system, it is often necessary to initially increase the line pressure in the system to a relatively high level and to subsequently decrease the line pressure at a downstream location in the system. “Line pressure” can be considered the pressure in a line or other flow path connecting a pressurized source to a downstream point in the system. The need for a relatively high initial line pressure and a lower downstream line pressure is especially evident in typical beverage delivery systems, which dispense liquid from a source located some distance from, and often underneath, the liquid outlet. The liquid must be pressurized to overcome gravitational forces and head losses that resist liquid flow from the liquid source to the liquid outlet. Furthermore, when the liquid to be dispensed at the outlet is carbonated, such as with beer or soda, the liquid must also be kept under pressure to prevent a loss of carbonation. However, the initial line pressure required for the system is often too high for proper subsequent dispensation at the outlet or other ultimate use of the liquid. This overpressurization is particularly detrimental in the field of carbonated beverage delivery because the overpressurization at the system's faucet will cause the liquid to be dispensed at a higher-than desired velocity, resulting in the dispensing of an overly-foamy beverage.
Prior art beverage dispensing systems that have addressed these problems have reduced line pressure by relying on head losses within an additional tubing section. Specifically, in some beer dispensing systems, the system is shipped to an intended installation with a standard length of Mayon tubing (typically 4.5′) as well as a standard additional length or “coolant loop” of copper tubing designed to provide the head losses required of a “typical” system. Then, the length of additional tubing actually required to create the correct restriction for that particular installation is determined, and the “standard” system is modified as necessary to provide the required restriction for that installation. In about 75% of systems, the “standard” restriction is inadequate, and as much as an additional 20′ of Mayon tubing must be installed in the system. The existing copper tubing coolant loop leads must be lengthened by means of soldering on extensions to match the length of Mayon tubing. The Mayon tubing is then secured to the coolant leads first with filament tape and then with a polymer tape. The coolant lines and Mayon tubing bundle are then insulated from the bottom of the dispensing head to the end of the leads with six foot sections of Armaflex insulation, and the seams of the Armaflex are glued and taped together. If less than “standard” restriction is required, some Mayon tubing must be removed from the system, and the coolant leads must be shortened to match the Mayon tubing. The tubing must then be taped and insulated as described above.
It can thus be seen that the extra tubing is cumbersome to use, especially in installations in which many liquid lines must be placed in a relatively small area, as in many taverns. It is also difficult to install. These problems are especially severe in systems having beer pumps. These systems typically operate at a minimum pressure of 25 psig and often supply beer to multiple faucets through a multi-way manifold. The constant applied pressure leads to a reduction in flow. Additional restriction therefore is required to maintain the natural carbonation level of the products within the system to avoid breakout of the carbon-dioxide from the beverage and resulting foaming at the faucet.
Hence, the need has arisen to provide a pressure reducer for a fluid delivery system that is compact and simple in construction, that is easy to install, and that can be easily tailored to meet the pressure reduction needs of a particular system.